# Calculating the interest on a series of loans

I am a college student and started my first week of C++ and we were given an assignment to convert a Java program that calculate the interest on a series of loans given the amount of the principal, the annual interest rate, and the number of days in a sentinel loop into C++.

Here is what we were given:

import java.util.Scanner;
public class ex311
{
public static void main(String[] args)
{
double principle, rate, interest;
int days;
Scanner sc = new Scanner(System.in);
System.out.print("Enter principle (-1 to end):  ");
principle = sc.nextDouble();
while (principle != -1)
{
System.out.print("Enter annual interest rate (as a decimal):  ");
rate = sc.nextDouble();
System.out.print("Enter number of days:  ");
days = sc.nextInt();
interest = principle * rate / 365 * days;
System.out.printf("Interest is %.2f\n", interest);
System.out.print("\nEnter principle (-1 to end):  ");
principle = sc.nextDouble();
}
}
}


This is what I have for the C++ converted code:

#include <iostream>

using namespace std;
void main()
{
double principle, rate, interest;
int days;
cout << "Enter principle (-1 to end)";
cin >> principle;
while (principle != -1)
{
cout << "Enter annual interest rate(as a decimal)";
cin >> rate;

cout << "Enter number of days";
cin >> days;

interest = principle * rate / 365 * days;
cout << "Interest is "<< interest;
cout << "Enter principle (-1 to end)";
cin >> principle;
}
}


I would like to know if there is a better way to go about this, as in making my code more efficient. I am aware that I should not be using void main, but this is how we're being taught for the time being.

• I'm still confused as to why someone would teach about using void main. But at least you know that it's wrong. Commented Sep 6, 2016 at 3:26
• I asked the same thing as well,but from what I was told today it's to just get the basics down. I am using the proper way while I practice on my own time. Commented Sep 7, 2016 at 17:11